Graft protection in bypass surgery: siRNA-mediated silencing of adhesion molecules
Tobias Walker1, Hans Peter Wendel, Claudia Raabe
1Department of Thoracic, Cardiac, and Vascular Surgery, Tübingen University Hospital, Tübingen, Germany. tobias.walker@med.uni-tuebingen.de
Insights
This study demonstrates that RNA interference effectively reduces leukocyte adhesion to blood vessel cells, offering a new strategy to prevent graft restenosis after coronary bypass surgery.
Area of Science:
- Biomedical Engineering
- Molecular Biology
- Cardiovascular Research
Background:
- Graft restenosis after coronary bypass grafting is a major clinical challenge.
- Leukocyte-endothelial interactions, mediated by adhesion molecules, are central to graft alterations.
- Current treatments lack sufficient efficacy in preventing graft failure.
Purpose of the Study:
- To investigate a novel therapeutic approach using RNA interference to block adhesion molecule expression.
- To inhibit leukocyte adhesion and transmigration, thereby protecting bypass grafts.
- To assess the efficacy of targeting specific adhesion molecules with short interfering RNA (siRNA).
Main Methods:
- Human venous endothelial cells (HVECs) were transfected with siRNA targeting E-selectin, ICAM, and VCAM.
- Leukocyte adhesion was measured using video-assisted microscopy in a flow chamber.
- Cells were stimulated with tumor necrosis factor to induce adhesion molecule expression.
Main Results:
- siRNA transfection significantly reduced leukocyte attachment to activated HVECs for each targeted adhesion molecule (p < 0.05).
- A combination of three siRNA sequences demonstrated the most significant reduction in leukocyte adhesion (p < 0.05).
- siRNA effectively inhibited adhesion molecule expression and subsequent leukocyte-endothelial interactions.
Conclusions:
- RNA interference, particularly using a cocktail of siRNAs, is a highly effective method to inhibit leukocyte-endothelial interactions.
- This approach offers a promising strategy for superior protection against graft restenosis in coronary bypass surgery.
- The study validates siRNA as a potent tool for modulating cellular adhesion pathways in vascular grafts.
Abstract:
The outcome of patients after coronary bypass grafting is greatly influenced by the type of graft material employed, especially regarding the rate of graft restenosis. Besides direct thrombotic events, the leukocyte-endothelial interaction modulated by adhesion molecules is identified to be the central cause leading to graft alterations. This study deals with a new therapeutic concept in order to achieve superior protection of a new bypass graft by blocking the adhesion molecule expression pathway with RNA interference to inhibit the initial leukocyte adhesion and transmigration. Leukocyte binding to adhesion molecules on activated human venous endothelial cells (HVECs) was determined by video-assisted microscopy in a flow chamber mimicking physiological conditions. The cells under study were sequentially transfected in a nonviral manner with specific short interfering RNA-sequences (siRNA) targeting E-selectin, intercellular adhesion molecule, and vascular adhesion molecule. After stimulation of adhesion molecule expression by tumor necrosis factor, a leukocyte-rich suspension was run through the chamber and the attaching leukocytes were counted. Transfection with specific siRNA targeting three different adhesion molecules resulted in a highly significant reduction of leukocyte attachment to activated HVECs in each case compared to the controls (p < 0.05). Transfection with a mixture out of all three siRNA-sequences showed the lowest leukocyte adhesion (p < 0.05) compared to the controls. siRNA-sequences inhibit the adhesion molecule expression on HVECs in an extremely effective way; not only in a single transfection of specific molecules but also in a parallel transfection of multiple sequences in one transfection. Accordingly, siRNA treatment significantly reduced adhesion of leukocyte cells to HVECs compared to controls. This study showed for the first time an effective knockdown of the leukocyte-endothelium interactions by transfection of HVECs with a cocktail consisting of three highly specific siRNAs against three different endothelial adhesion molecules.
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